package loop

import (
	"testing"
	"time"

	"github.com/kami/maven/internal/store"
)

// ----------------------------- ExplainGate --------------------------------

func TestExplainGate_AllPass(t *testing.T) {
	now := refTime()
	s := State{Now: now, Presence: store.Present}
	r := Rule{Name: "test", Severity: Sev3, Predicate: func(State) bool { return true }}
	passed, blocked, d := ExplainGate(s, r)
	if !passed {
		t.Fatalf("all-pass gate: want passed, blocked by %q; detail=%+v", blocked, d)
	}
}

func TestExplainGate_Snooze(t *testing.T) {
	now := refTime()
	s := State{
		Now:         now,
		Presence:    store.Present,
		SnoozeUntil: map[string]time.Time{"water": now.Add(time.Hour)},
		Facts:       map[string]store.Fact{"water": factAt("water", "tap:water", `"250ml"`, now.Add(-4*time.Hour))},
	}
	r := WaterRule()
	passed, blocked, d := ExplainGate(s, r)
	if passed || blocked != "snooze" {
		t.Fatalf("snooze: want blocked=snooze, got passed=%v blocked=%q", passed, blocked)
	}
	if d.SnoozeUntil == nil || !d.SnoozeUntil.Equal(now.Add(time.Hour)) {
		t.Fatalf("snooze-until missing or wrong: %v", d.SnoozeUntil)
	}
}

func TestExplainGate_Cooldown(t *testing.T) {
	now := refTime()
	s := State{
		Now:           now,
		Presence:      store.Present,
		CooldownUntil: map[string]time.Time{"water": now.Add(10 * time.Minute)},
		Facts:         map[string]store.Fact{"water": factAt("water", "tap:water", `"250ml"`, now.Add(-4*time.Hour))},
	}
	r := WaterRule()
	passed, blocked, d := ExplainGate(s, r)
	if passed || blocked != "cooldown" {
		t.Fatalf("cooldown: want blocked=cooldown, got passed=%v blocked=%q", passed, blocked)
	}
	if d.CooldownUntil == nil || !d.CooldownUntil.Equal(now.Add(10*time.Minute)) {
		t.Fatalf("cooldown-until missing or wrong: %v", d.CooldownUntil)
	}
}

func TestExplainGate_QuietHours(t *testing.T) {
	now := refTime()
	s := State{Now: now, Presence: store.Present, QuietHours: true}
	r := WaterRule() // Sev1 — care
	passed, blocked, _ := ExplainGate(s, r)
	if passed || blocked != "quiet_hours" {
		t.Fatalf("quiet hours: want blocked=quiet_hours, got passed=%v blocked=%q", passed, blocked)
	}
}

func TestExplainGate_QuietHoursOpsBypass(t *testing.T) {
	now := refTime()
	s := State{Now: now, Presence: store.Present, QuietHours: true,
		Facts: map[string]store.Fact{"netdata_alarm": factAt("netdata_alarm", "poll:netdata", `"critical"`, now.Add(-1*time.Minute))},
	}
	r := NetdataCriticalRule() // Sev3 — ops
	passed, blocked, d := ExplainGate(s, r)
	if !passed {
		t.Fatalf("ops sev3 should bypass quiet hours, blocked=%q detail=%+v", blocked, d)
	}
}

func TestExplainGate_CalendarBusy(t *testing.T) {
	now := refTime()
	s := State{Now: now, Presence: store.Present, CalendarBusy: true}
	r := WaterRule() // Sev1
	passed, blocked, _ := ExplainGate(s, r)
	if passed || blocked != "calendar_busy" {
		t.Fatalf("calendar busy: want blocked=calendar_busy, got passed=%v blocked=%q", passed, blocked)
	}
}

func TestExplainGate_PresenceAway(t *testing.T) {
	now := refTime()
	s := State{Now: now, Presence: store.Away}
	r := WaterRule() // Sev1 care
	passed, blocked, d := ExplainGate(s, r)
	if passed || blocked != "presence" {
		t.Fatalf("presence away: want blocked=presence, got passed=%v blocked=%q detail=%+v", passed, blocked, d)
	}
	if d.Presence != "away" {
		t.Fatalf("detail presence: want away, got %q", d.Presence)
	}
}

func TestExplainGate_PresenceAwayOpsBypass(t *testing.T) {
	now := refTime()
	s := State{Now: now, Presence: store.Away,
		Facts: map[string]store.Fact{"service_down": factAt("service_down", "poll:uptimekuma", `"down"`, now.Add(-1*time.Minute))},
	}
	r := ServiceDownRule() // Sev4 ops
	passed, blocked, d := ExplainGate(s, r)
	if !passed {
		t.Fatalf("ops sev4 should bypass away, blocked=%q detail=%+v", blocked, d)
	}
}

func TestExplainGate_InertNoData(t *testing.T) {
	now := refTime()
	s := State{Now: now, Presence: store.Present} // no facts at all
	r := WaterRule()                              // InertWhenNoData: ["water"]
	passed, blocked, d := ExplainGate(s, r)
	if passed || blocked != "inert_no_data" {
		t.Fatalf("inert: want blocked=inert_no_data, got passed=%v blocked=%q", passed, blocked)
	}
	if len(d.InertKeysMissing) != 1 || d.InertKeysMissing[0] != "water" {
		t.Fatalf("inert keys: want [water], got %v", d.InertKeysMissing)
	}
}

func TestExplainGate_AllBlockersOrdered(t *testing.T) {
	// Snooze is checked before cooldown, quiet hours, etc.
	now := refTime()
	s := State{
		Now:           now,
		Presence:      store.Present,
		SnoozeUntil:   map[string]time.Time{"water": now.Add(time.Hour)},
		CooldownUntil: map[string]time.Time{"water": now.Add(10 * time.Minute)},
		QuietHours:    true,
	}
	r := WaterRule()
	_, blocked, d := ExplainGate(s, r)
	if blocked != "snooze" {
		t.Fatalf("snooze should be checked first: got blocked=%q", blocked)
	}
	if d.SnoozeUntil == nil {
		t.Fatal("snooze-until should be set")
	}
}

// ----------------------------- ExplainTick --------------------------------

func TestExplainTick_NothingFires(t *testing.T) {
	now := refTime()
	s := State{Now: now, Presence: store.Away}
	cand, trace := ExplainTick(s, DefaultRules())
	if cand != nil {
		t.Fatalf("nil candidate expected, got %+v", cand)
	}
	if trace.Winner != "" {
		t.Fatalf("empty winner expected, got %q", trace.Winner)
	}
	if !trace.Now.Equal(now) {
		t.Fatalf("trace now mismatch")
	}
	if len(trace.RuleTraces) != len(DefaultRules()) {
		t.Fatalf("expected %d rule traces, got %d", len(DefaultRules()), len(trace.RuleTraces))
	}
}

func TestExplainTick_OneFires(t *testing.T) {
	now := refTime()
	s := State{
		Now:      now,
		Presence: store.Present,
		Facts: map[string]store.Fact{
			"water": factAt("water", "tap:water", `"250ml"`, now.Add(-4*time.Hour)),
		},
	}
	cand, trace := ExplainTick(s, DefaultRules())
	if cand == nil || cand.Rule.Name != "water" {
		t.Fatalf("want water candidate, got %+v", cand)
	}
	if trace.Winner != "water" {
		t.Fatalf("winner water, got %q", trace.Winner)
	}

	var found bool
	for _, r := range trace.RuleTraces {
		if r.RuleName == "water" {
			found = true
			if !r.PredicateResult {
				t.Error("water predicate should be true")
			}
			if !r.GateResult {
				t.Error("water gate should be true")
			}
			if !r.WasSelected {
				t.Error("water should be selected")
			}
		}
	}
	if !found {
		t.Fatal("water rule not in trace")
	}
}

func TestExplainTick_Tiebreak(t *testing.T) {
	// Two rules with same severity — alphabetically first should win.
	now := refTime()
	s := State{
		Now:      now,
		Presence: store.Present,
		Facts: map[string]store.Fact{
			"water": factAt("water", "tap:water", `"250ml"`, now.Add(-4*time.Hour)),
			"meal":  factAt("meal", "tap:meal", `"pizza"`, now.Add(-7*time.Hour)),
		},
	}
	cand, trace := ExplainTick(s, []Rule{MealRule(), WaterRule()})
	if cand == nil {
		t.Fatal("expected a candidate")
	}
	// Both Sev1, "meal" < "water" alphabetically → meal wins
	if cand.Rule.Name != "meal" {
		t.Fatalf("tiebreak: want meal, got %q", cand.Rule.Name)
	}
	if trace.Winner != "meal" {
		t.Fatalf("winner should be meal, got %q", trace.Winner)
	}

	// meal was selected, water lost to meal
	var waterFound, mealFound bool
	for _, r := range trace.RuleTraces {
		switch r.RuleName {
		case "water":
			waterFound = true
			if r.LostTo != "meal" {
				t.Errorf("water.LostTo = %q, want meal", r.LostTo)
			}
			if r.WasSelected {
				t.Error("water should not be selected in tiebreak")
			}
		case "meal":
			mealFound = true
			if !r.WasSelected {
				t.Error("meal should be selected")
			}
			if r.LostTo != "" {
				t.Errorf("meal.LostTo = %q, want empty", r.LostTo)
			}
		}
	}
	if !waterFound || !mealFound {
		t.Fatal("both rules should be in trace")
	}
}

func TestExplainTick_WinnerRecorded(t *testing.T) {
	now := refTime()
	// water (Sev1) and service_down (Sev4) both want to fire.
	s := State{
		Now:      now,
		Presence: store.Present,
		Facts: map[string]store.Fact{
			"water":        factAt("water", "tap:water", `"250ml"`, now.Add(-4*time.Hour)),
			"service_down": factAt("service_down", "poll:uptimekuma", `"down"`, now.Add(-1*time.Minute)),
		},
	}
	cand, trace := ExplainTick(s, DefaultRules())
	if cand == nil || cand.Rule.Name != "service_down" {
		t.Fatalf("max severity wins: want service_down, got %+v", cand)
	}
	if trace.Winner != "service_down" {
		t.Fatalf("winner = %q, want service_down", trace.Winner)
	}

	// water lost to service_down
	var waterLost bool
	for _, r := range trace.RuleTraces {
		if r.RuleName == "water" && r.LostTo == "service_down" {
			waterLost = true
		}
	}
	if !waterLost {
		t.Error("water should show lost_to=service_down")
	}
}

func TestExplainTick_GateBlockedRecorded(t *testing.T) {
	now := refTime()
	s := State{
		Now:        now,
		Presence:   store.Present,
		QuietHours: true,
		Facts: map[string]store.Fact{
			"water": factAt("water", "tap:water", `"250ml"`, now.Add(-4*time.Hour)),
		},
	}
	_, trace := ExplainTick(s, DefaultRules())
	for _, tr := range trace.RuleTraces {
		if tr.RuleName == "water" {
			if tr.GateBlockedBy != "quiet_hours" {
				t.Errorf("water blocked by %q, want quiet_hours", tr.GateBlockedBy)
			}
			if tr.PredicateResult != true {
				t.Error("water predicate should be true")
			}
			if tr.GateResult != false {
				t.Error("water gate should be false")
			}
		}
	}
}